Pitch assembly for a wind turbine rotor blade

Abstract

The present disclosure is directed to a pitch assembly for coupling a rotor blade to a hub of a wind turbine. In one embodiment, the pitch assembly includes a first pitch bearing having a first outer race and a first inner race rotatable relative to the first outer race via a first set of rolling elements, a second pitch bearing having a second outer race and a second inner race rotatable relative to the second outer race via a second set of rolling elements, and at least one spacer configured axially between and contacting the first and second pitch bearings. Further, at least a portion of the first pitch bearing and at least a portion of the second pitch bearing are axially aligned between the rotatable hub and the rotor blade in a generally span-wise direction.

What is claimed is: 
     
       1. A rotor blade assembly for a wind turbine, comprising;
 a rotatable hub; 
 at least one rotor blade configured with the rotatable hub and comprising a root end and a tip end, the at least one rotor blade defining a longitudinal axis from the root end to the tip end that is parallel with a pitch axis of the rotor blade; and, 
 a pitch assembly coupling the root end of the rotor blade to the rotatable hub and configured to rotate the at least one rotor blade about the pitch axis, the pitch assembly comprising:
 a first pitch bearing having a first outer race and a first inner race rotatable relative to the first outer race via a first set of rolling elements, 
 a second pitch bearing having a second outer race and a second inner race rotatable relative to the second outer race via a second set of rolling elements, the first and second outer races being mounted to the rotatable hub via one or more fasteners, the second inner race being mounted to the rotor blade via one or more fasteners, the first inner race abutting against an outer surface of a blade root of the rotor blade and secured thereto via an interference fit, the first inner race and the second inner race are not aligned in an axial direction, the axial direction being parallel with the pitch axis, and 
 at least one spacer configured axially between and contacting the first and second pitch bearings. 
 
 
     
     
       2. The rotor blade assembly of  claim 1 , wherein at least a portion of the first pitch bearing and at least a portion of the second pitch bearing are axially aligned between the rotatable hub and the rotor blade in a span-wise direction. 
     
     
       3. The rotor blade assembly of  claim 1 , wherein the at least one spacer is configured between at least one of the first and second outer races or the first and second inner races. 
     
     
       4. The rotor blade assembly of  claim 3 , wherein the at least one spacer is configured to form at least one continuously smooth surface with at least one of the first and second outer races or the first and second inner races of the first and second pitch bearings. 
     
     
       5. The rotor blade assembly of  claim 1 , wherein the at least one spacer comprises a circular shape corresponding to the cross-sectional shape of at least one of the first or second inner or outer races. 
     
     
       6. The rotor blade assembly of  claim 1 , wherein the first outer race is axially aligned with the second outer race in the span-wise direction. 
     
     
       7. The rotor blade assembly of  claim 5 , wherein the first and second sets of rolling elements are axially aligned in the span-wise direction. 
     
     
       8. The rotor blade assembly of  claim 1 , wherein the first pitch bearing is smaller than the second pitch bearing.